Cab Monitors are going through an extensive streamlining. This year TeeJet, Dickey-john and the Big 4 tractor makers — AGCO, New Holland, Case IH and John Deere — all introduced new or upgraded versions of virtual terminals (VTs) for use in tractors.

VTs make it possible to view (and in some cases control) not only tractor functions but also implement functions, regardless of brand, from a single monitor. In the past, as many as six monitors may have been required to do the same functions. This upgrade has been made possible by an electronic communications standard called ISO 11783, commonly called ISOBUS.

“The goal of the ISO standard is to allow single point control of all implements from one monitor in the cab called a virtual terminal,” says Rich Gould, vice president of TeeJet Technologies. “Tractors will ultimately have just one monitor instead of multiple devices to control planters, sprayers, spreaders and other implements.”

Experts say this offering will be a win for buyers. But it also brings to bear some questions, such as: What functions should a VT control? And will it replace the need for aftermarket display screens?

These questions are fueling a battle for the cab as manufacturers duke it out to retain display space and operating control of your tractor and implement functions.

That battle began with the advent of electronic controllers on implements and tractors. In the early 1990s, companies started to convert mechanical functions to electromechanical or electrohydraulic controls. Engineers put motors, circuits and wires onto valves and other components so operators could control functions from the cab rather than having to get out of the seat to move a lever.

While electronics added convenience, they also added clutter. Each electronic function required its own monitor, wiring harness and electronic control unit (ECU), called the “black box” or “brains,” which blocked visibility. Marvin Stone, a professor at Oklahoma State University, coined the term “monitor wallpaper” to describe the array of displays and peripherals that were lining the A-posts and glass in tractor cabs.

Then, later in the '90s, an automotive standard called Controller Area Network (CAN) was used to reduce the amount of hardware required. CAN technology enabled engineers to network electronic devices using a single group of wires called a serial “bus.”

However, while CAN Bus consolidated hardware, it still didn't eliminate it because each company used proprietary messaging and only same-brand components could be hardwired together. “We had our system, Deere, Case IH and New Holland had theirs, and none of them could cross data back and forth,” says Wade Stewart, product manager with AutoFarm who worked for AGCO at the time he was interviewed for this story. Farmers who used different brands of electronics were still stuck with multiple peripherals and wiring harnesses that would have to be fished out the back window to reach the implement.

Observers say the problem was analogous to adoption of hydraulics 40 or 50 years ago before the industry agreed to a standard hydraulic connection that made it easy to connect one brand of implement to different brands of tractors.

In 2000, machinery manufacturers agreed to implement a similar standard for electrical connections. The standard, called ISO 11783 or ISOBUS, is based on the CAN Bus system. It originated in Europe, where mixed fleets on farms are common due to the high number of short-line companies. In Europe, ISOBUS equipment has been readily available for at least the past three years.

Adoption here in the U.S. has been slower. “Trying to get everyone to agree on the standard is like trying to part the Red Sea,” says AutoFarm's Stewart. “Our meetings have been compared to the United Nations'.”

In 2002, the North American ISOBUS Implementation Taskforce (NAIITF ) was formed to promote the industry's adoption of the standard. William Rudolph, NAIITF's general chair, says the standard has been in published, usable form for the last four years. Some parts are still being revised.

Who's compliant?

“Under the standard, any ISOBUS-compliant implement from any manufacturer can be displayed and controlled using the built-in user terminal that comes with the ISOBUS-compliant tractor,” Rudolph says. Compliance is determined by an independent testing lab appointed by NAIITF.

Companies practice for the test by attending “Plug Fests,” which are informal demonstrations of connectability between different manufacturers' devices. Connection is made through a standard plug called a “breakaway connector.”

To date, all four of the major original equipment manufacturers (OEMs) have active ISOBUS development programs and have introduced ISO-compliant products. (For a partial listing of ISOBUS-compliant devices, visit www.isobus.com/isobus_E/isobus.html.) Rudolph says the major electronics suppliers are also heavily involved in ISOBUS development in order to remain competitive.

Resistance, he says, has been mostly from second-tier equipment manufacturers for two reasons. “First there have not been a lot of tractors equipped with ISOBUS until just recently, so there has not been a need for second-tier manufacturers to invest in ISOBUS development,” he says. “Secondly, public awareness of the technology is low, so there has been little demand from customers.” He expects both issues to dissolve as more equipment comes standard-equipped with ISOBUS technology.